Method and system for announcing traffic engineering parameters of composite transport groups

ABSTRACT

An approach is provided for announcing aggregate characteristics of a composite transport group (CTG) for traffic engineering. Information specifying characteristics of a plurality of component links of the CTG is received. An aggregate characteristic of the CTG is determined based the information. The aggregate characteristic is announced to a label switched network for provisioning label switched paths on the CTG.

BACKGROUND INFORMATION

Telecommunication networks have developed from connection-oriented,circuit-switched (CO-CS) systems, such as the public switched telephonenetwork (PSTN), utilizing constant bit-rate, predefined point-to-pointconnections to connectionless, packet-switched (CNLS) systems, such asthe Internet, utilizing dynamically configured routes characterized byone or more communication channels divided into arbitrary numbers ofvariable bit-rate channels. With the increase in demand for broadbandcommunications and services, telecommunication service providers arebeginning to integrate long-distance, large-capacity opticalcommunication networks with these traditional CO-CS and CNLS systems.Typically, these optical communication networks utilize multiplexingtransport techniques, such as time-division multiplexing (TDM),wavelength-division multiplexing (WDM), and the like, for transmittinginformation over optical fibers. However, an increase in demand for moreflexible, resilient transport is driving optical communication networkstoward high-speed, large-capacity packet-switching transmissiontechniques that enable switching and transport functions to occur incompletely optical states via one or more packets. This technologicalinnovation carries with it a new burden to provision reliable serviceover these networks, i.e., service that is capable of withstanding linkand node failure while also maintaining high transmission capacity. As aresult, traffic engineering plays an important role in providing highnetwork reliability and performance. However, given that a multitude ofnetworks operate using various protocols, there is a continual challengefor service providers to ensure proper exchange of traffic engineeringparameters across networks.

Therefore, there is a need for an approach that provides for effectiveand efficient announcement of traffic engineering parameters acrossmultiple networks.

BRIEF DESCRIPTION OF THE DRAWINGS

Various exemplary embodiments are illustrated by way of example, and notby way of limitation, in the figures of the accompanying drawings inwhich like reference numerals refer to similar elements and in which:

FIG. 1 is a diagram of a system configured to support trafficengineering parameter announcement for composite transport groups,according to an exemplary embodiment;

FIG. 2 is a diagram of a composite transport group, according to anexemplary embodiment;

FIG. 3 is a diagram of an optical node configured to provide compositetransport groups, according to an exemplary embodiment;

FIG. 4 is a flowchart of a process for establishing a compositetransport group, according to an exemplary embodiment;

FIG. 5 is a diagram of a control module configured to determine andannounce traffic engineering parameters of composite transport groups,according to an exemplary embodiment;

FIG. 6 is a flowchart of a process for announcing traffic engineeringparameters of composite transport groups, according to an exemplaryembodiment;

FIG. 7 is a flowchart of a process for routing traffic over a compositetransport group based on announced traffic engineering parameters,according to an exemplary embodiment; and

FIG. 8 is a diagram of a computer system that can be used to implementvarious exemplary embodiments.

DESCRIPTION OF THE PREFERRED EMBODIMENT

A preferred apparatus, method, and software for announcing trafficengineering parameters for composite transport groups are described. Inthe following description, for the purposes of explanation, numerousspecific details are set forth in order to provide a thoroughunderstanding of the preferred embodiments of the invention. It isapparent, however, that the preferred embodiments may be practicedwithout these specific details or with an equivalent arrangement. Inother instances, well-known structures and devices are shown in blockdiagram form in order to avoid unnecessarily obscuring the preferredembodiments of the invention.

Although the various exemplary embodiments are described with respect totraffic engineering (TE) parameter advertisement over a multi-protocollabel switching (MPLS) network, it is contemplated that the variousexemplary embodiments are also applicable to other equivalenttechnologies and transport networks.

FIG. 1 is a diagram of a system configured to support trafficengineering parameter announcement for composite transport groups,according to an exemplary embodiment. For the purposes of illustration,a system 100 provides advertisement of traffic engineering (TE)parameters (or aggregate characteristics) of composite transport groups(CTG) established between client nodes (e.g., node 101) and one or moreoptical nodes (e.g., optical nodes 103 and 105) within a packet-switchedoptical infrastructure. By way of example, the system 100 encompassesnetworks of disparate service providers: service provider “A” andservice provider “B.” In this manner, optical links 107 and 109 may beconsidered “off-network” links (i.e., transport channels extendingbetween network 111 of service provider “A” and autonomous systems (AS)113 and 115 of service provider “B”), while optical link 117 may beconsidered an “on-network” link (i.e., a transport channel extendingbetween AS 113 and 115 of service provider “B”). It is noted that in analternative embodiment, AS 113 and 115 can be sub-networks of a singleAS. In certain embodiments, client (subscriber or customer) node 101 iscustomer premise equipment (CPE) with optical nodes 103 and 105 undercontrol of a service provider, which in this instance is serviceprovider “B.” Additionally, it is contemplated that node 101 can beowned by the service provider. While specific reference will be madethereto, it is contemplated that system 100 may embody many forms andinclude multiple and/or alternative components and facilities.

Traffic engineering (TE), i.e., the ability to control and manipulatethe flow of network traffic, has the capability to alleviate this burdenvia resource reservation, fault-tolerance, and optimization oftransmission resources. Composite transport groups (CTG), i.e., logicalbundling of physical and/or logical links that are viewed by high layerrouting and switching protocols as single logical interfaces, can alsolessen the burden by simplifying bandwidth management, improvingbandwidth utilization, and delivering cost-effective protection schemes.However, before network traffic can be engineered onto CTGs, thecharacteristics (or parameters) of the CTGs must be announced to thetransport network.

It is recognized that multi-protocol label switching (MPLS) trafficengineering (TE) has been developed to provide network administratorswith the ability to control and manipulate the flow of traffic through anetwork. MPLS-TE utilizes label switching techniques to construct labelswitched paths (LSP) on links interconnecting nodes of a network.Routing protocols, such as open-shortest path first (OSPF) andintermediate system to intermediate system (IS-IS), are utilized todetermine LSP routes through the network, as well as govern thedistribution of routing information between nodes of the network. OSPFand IS-IS utilize various attributes characterizing the links, such asavailable bandwidth, administration cost, etc., to determine LSP routesand, thereby, require nodes of the network to report (or announce) thesecharacteristics concerning any directly connected links. It is notedthat these attributes (or characteristics) may also be referred to as TEparameters. Unfortunately, as the topology of modern day transportnetworks become more and more complex, the announcement and utilizationof TE parameters becomes increasingly onerous and inefficient.

Therefore, the approach of system 100, according to certain embodiments,stems from the recognition that provisioning CTGs in support of MPLS-TElogically reduces the complexity of network topology, as well as reducesthe amount of TE parameters that must be announced. In turn, MPLS-TE isenhanced and routing scalability is improved. This is because CTGsmanage sets of “component connections” (i.e., logical channels ) as“composite connections,” as well as manage associations between clientnode instances and composite connections, which enable CTGs todynamically distribute network traffic over the component connectionstransparently from the nodes transmitting and receiving a flow oftraffic. In other words, CTGs, among other features, enable individualpathways to carry network traffic from multiple client nodes, maintainindependent pathway transport availabilities and capacities, and providefor disparate transport rates, all the while enabling these individualpathways to provide pathway protection for one another. Furthermore,provisioning CTGs in support of MPLS-TE only requires the CTGs to beannounced as single TE pathways that are characterized by aggregate TEparameters, instead of having to individually report a multitude ofcomponent connections and their mass of associated TE parameters.Namely, when an LSP is established, only the aggregate CTG pathway needbe identified, such that provisioning the LSP over the CTG becomes alocal matter transparently resolved by the CTG, as opposed to the nodestransmitting and receiving the flow of traffic.

According to one embodiment, system 100 supports TE parameterannouncement based on the configuration of a CTG established between aclient node 101, such as a client device, router, switch, or any othersuitable customer premise equipment (CPE) (or Provider Edge (PE)), andtwo or more optical nodes, (e.g., optical nodes 103 and 105), such as areconfigurable optical add/drop multiplexer (ROADM), or other suitableoptical transport platform (e.g., P-OTP (packet optical transportplatform)). That is, an aggregate characteristic of the CTG may bedetermined and announced to other (or external) network based on andusing individual characteristics of the plurality of component links (orconnections) forming the CTG. The aggregate characteristics can beviewed as “external parameters”—i.e., external to the CTG network, whilethe individual characteristics can be referred to “internal parameters.”

It is noted that CTGs of system 100 may be configured to supportconnection-oriented flows, e.g., network traffic embodying, for example,information packetized into one or more packets. Connectionlesscommunications may also be encapsulated within connection-orientedconnections. In exemplary embodiments, one CTG (or composite connection)may be established for transport of network traffic from client node 101to optical node 103, and may include a first set (or bundle) of logicalchannels (or component connections), while another CTG may beestablished for transport of network traffic from client node 101 tooptical node 105, and may include a second set of logical channels. Thefirst set of logical channels may include a logical channel defined byoptical link 107 (e.g., a primary channel) and a logical channel definedby the conjunction of optical links 109 and 117 (e.g., a secondarychannel). The second set of logical channels may include a logicalchannel defined by optical link 109 (e.g., a primary channel) and alogical channel defined by the conjunction of optical links 107 and 117(e.g., a secondary channel). It is contemplated; however, that logicalchannels may also be grouped in multiple CTGs.

The characteristics of the component links (i.e., CTG internalparameters), according to particular embodiments, may correspond tocomponent link administrative costs (or TE metrics), physical bandwidthsof the component links, connections (or pathways) on the component linksconsuming bandwidth, connection placement priorities, connection holdingpriorities, and/or connection over-subscription factors. In turn, theaggregate characteristic (i.e., CTG external parameters) of the CTG maycorrespond to a CTG administrative cost utilized in shortest pathcomputations, a CTG available bandwidth for supporting one or more LSPson the CTG, and/or a maximum LSP bandwidth capable of being provisionedon the CTG. In exemplary embodiments, one or more of these aggregatecharacteristics, such as the CTG available bandwidth and/or the maximumLSP bandwidth, may be determined and announced per priority (e.g., classof service).

According to other embodiments, network traffic may be transparentlyrouted over a CTG based on one or more aggregate characteristics of theCTG. That is, a pathway, such as a label switched pathway, may beestablished over the CTG by a transmitting node (e.g., client node 101)and a receiving node (e.g., node 103 or 105); however, the CTG mayindependently provision the pathway onto one or more componentconnections of the CTG. In this manner, system 100 permits node 101 totreat CTGs as physical trunks, whereas the CTGs handle the routing oftraffic on its own. This preserves the configurations at node 101, aswell as at optical nodes 103, 105. Thus, the use of CTGs can, forinstance, save up to 50% access cost compared to traditional systems.Further, CTGs can also save up to 50% on port costs. Further, customerprovisioning can be simplified at node 101 and MPLS-TE can be moreeasily and efficiently applied.

As seen in FIG. 1, system 100 includes networks 111, 113, and 115, whichinclude nodes 101, 103, and 105, respectively. In exemplary embodiments,system 100 is a connection-oriented transport environment having one ormore optical links (e.g., optical links 107-109) established therein,wherein individual optical links embody optical fibers configured tocarry data between two nodes, e.g., between nodes 101 and 103. It isnoted that optical links 107, 109, and 117 may be automatically setupand torn down by means of any suitable signaling protocol, e.g., labeldistribution protocol (LDP), targeted LDP (TLDP), resource reservationprotocol for traffic engineering (RSVP-TE), etc. Accordingly, opticallinks 107, 109, and 117 may carry information over various wavelengthsor “channels.” Routing protocols may include OSPF, IS-IS, border gatewayprotocol (BGP), interior gateway protocol (IGP), or any other suitablelink-state or optimized link-state routing protocol.

Networks 113-115 may be any type of wired and/or wireless transportnetwork, such as a local area network (LAN), metropolitan area network(MAN), wide area network (WAN), etc. At least a portion of networks113-115 comply with the International TelecommunicationsUnion-Telecommunication (ITU-T) standards recommendation working draftG.800 titled, “Unified Functional Architecture of Transport Networks,”which is incorporated herein, by reference, in its entirety. Further,networks 113-115 may be configured to support MPLS-TE.

Client node 101 may be any suitable customer premise equipment, such asa computing device, router, switch, etc., while optical nodes 103 and105 may be any suitable optical transport platform, such as a terminalmultiplexor, a reconfigurable add/drop multiplexer, photonic switch,optical cross-connect with optical-electrical-optical conversion,synchronous optical networking cross-connect, signal regenerator,router, switch, or any other suitable optical networking interface, suchas a packet optical transport platform.

Accordingly, information transport can occur between nodes 101-105 ofnetworks 111-115 via optical links 107, 109, and 117, which representchannels (or paths) along which packets may be transported. As such, atopology of system 100 can be characterized via optical links 107, 109,and 117, which further characterize the available transport capacity(e.g., bandwidth capacity) between nodes 101-105 of networks 113-115.Thus, during optical link configuration, optical links 107, 109, and 117may be established and grouped into one or more CTGs for provisioningnetwork traffic among and between nodes 101-105. As such, CTGs givenodes 101-105 the property of adjacency when viewed by higher layernetworking protocols, such as OSPF, IS-IS, etc.

FIG. 2 is a diagram of a composite transport group, according to anexemplary embodiment. As shown, composite connection 201 is madeavailable via CTG 203, which includes one or more parallel componentconnections (e.g., physical and/or logical links), e.g., componentconnections 205 a-205 m, sharing similar ingress and egress points.Accordingly to one embodiment, CTG 203 ingress and egress pointscorrespond to nodes 101-105. For instance, node 101 may be an ingresspoint of two CTGs, while nodes 103 and 105 may be respective egresspoints of the two CTGs. Additionally, nodes 103 and 105 may embody “nethop” nodes on a path of the CTGs, i.e., on a path of a componentconnection of a CTG.

From the perspective of CTG 203, each component connection 205 a-205 macts as an independent transportation entity, and therefore, enablesindependent transportation path availabilities (e.g., physical and/oravailable bandwidths) for composite connection 201 for network traffic.That is, if network traffic is sequenced at an ingress point andtransported over one or more component connections (e.g., componentconnections 205 a-205 m), then the network traffic may or may not arriveat an egress point in the same sequential order. Thus, when informationis transported via composite connection 201 utilizing CTG 203, a layerprocessor (LP) at the ingress (e.g., LP 207) distinguishes componentconnections 205 a-205 m by processing each packet and distributing thepackets over composite connection 201 via one or more of componentconnections 205 a-205 m. The ability of LP 207 to distinguish betweencomponent connections 205 a-205 m is dependent upon packet header formatand information encoded therein, such as one or more labels forlabel-switch routing. Thus, LP 207 routes network traffic transparentlyfrom the entities attempting to transport and receive the traffic. Inthis manner, a network gains transport scalability via compositeconnection 201 because individual component connections can beindependently added, removed, and/or resolved by CTG 203, and since thetransportation entities are only privy to the fact that compositeconnection 301, as a whole, is operational, the configuration of thetransportation entities need not be affected.

Thus, composite connection 201 made available via CTG 203 can be appliedin both connection-less packet-switched (CL-PS) optical networks, aswell as in connection-oriented packet-switched (CO-PS) optical networks.In CL-PS environments, component connections 205 a-205 m can exist aspoint-to-point links between autonomous systems (e.g., autonomoussystems 113 and 115). Optical nodes 103 and 105 utilize informationencoded in packet headers provided by, for example, client nodes (e.g.,node 101) to distinguish between client communications. That is, aprocessing entity (or control interface) of optical nodes 103 and 105utilize this information to differentiate between component connections(e.g., component connections 205 a-205 m) and distribute network trafficover one or more CTGs (e.g., CTG 203). Thus, network traffic transportedvia CTG 203 is “seen” by client nodes (e.g., node 101) as “belonging” tocomposite connection 201, as opposed to the particular componentconnection 205 a-205 m “actually” supporting the flow of networktraffic.

In CO-PS environments, component connections 205 a-205 m of CTG 203 canbe configured as point-to-point links, as above, or as point-to-pointpaths. Paths may be established over one or more optical links (e.g.,optical links 107, 109, and/or 117) and, thereby, traverse one or morenodes (e.g., nodes 101-105). For composite connection 201 to supportmultiple communications from client nodes (e.g., node 101) informationmay be encoded within individual packet headers to differentiate betweencommunications. Accordingly, at composite connection 201 ingress, LP 207can use this information to distribute packets over componentconnections 205 a-205 m, which enables multiple composite connections201 to be configured over a CTG, such as CTG 203. Further, LP 207 may,when determining which component connection to utilize to supporttransport, use this information to perform traffic engineering androuting processes, e.g., to assign resource capacity or priority forindividual communications. In particular embodiments, this informationmay be acquired from a network administrator or network managementsystem (not shown), as opposed to the packet headers. Thus, a compositeconnection 201 may be traffic engineered per component connections 205a-205 m, as well as traffic engineered based on component connectionattributes, e.g., bandwidth capability, operational status,over-subscription, and the like, or node 101 attributes, e.g., allocatedcapacity, priority, origination address, destination address, etc.

FIG. 3 is a diagram of an optical node configured to provide compositetransport groups, according to an exemplary embodiment. For descriptivepurposes, optical node 300 is described with respect to packetswitching; however, may include functionality for optical burstswitching, time division multiplexing (TDM), wavelength-divisionmultiplexing (WDM), or any other suitable signal transfer schemes. Asshown, optical node 300 includes input line cards 301 a-301 n, outputline cards 303 a-303 n, control interface 305, and optical switchsection 307; however, it is contemplated that optical node 300 mayembody many forms. For example, optical node 300 may comprise computinghardware (such as described with respect to FIG. 8), as well as includeone or more components configured to execute the processes describedherein for establishing CTGs and/or announcing TE parameters of a CTGsupported by optical node 300. Furthermore, it is contemplated that thecomponents of optical node 300 may be combined, located in separatestructures, or separate physical locations. In other words, a specifictopology is not critical to embodiments of optical node 300 or system100 for that matter.

According to one embodiment, input line cards 301 a-301 n act as “n”input interfaces (ingress points) to optical node 200 from “n”transmitting sources (e.g., node 101), while output line cards 303 a-303n act as “n” output interfaces (egress points) from optical node 300 to“n” destination nodes (e.g., optical nodes 103 and 105). When packetsarrive at optical node 300, input line cards 301 a-301 n port packets toreceiving interface 309 of optical switch section 307. Receivinginterface 309 separates headers and payloads from individual packets.Header information is provided to control interface 305 for routingpurposes, while payloads are switched to destination output line cards303 a-303 b via hybrid switching fabric 311 and sending interface 313.That is, hybrid switching fabric 311 routes payloads to appropriatepathways on sending interface 313, whereby updated headers are combinedwith switched payloads. The combination is output to destination nodesvia output line cards 303 a-303 n.

In particular implementations, control interface 305 is configured toprovision one or more logical channels through hybrid switching fabric311 based on system 100 topological information. These logical channelscan be grouped into one or more CTGs. According to one embodiment,control interface 305 establishes the aforementioned CTGs for transportof network traffic from client node 101 to optical node 103, and fromclient node 101 to optical node 105.

FIG. 4 is a flowchart of a process for establishing and announcing acomposite transport group, according to an exemplary embodiment. Forillustrative purposes, process 400 is described with reference to FIGS.1 and 2. It is noted that process 400 assumes the existence of one ormore previously established (or constructed) physical connections (e.g.,optical links 107, 109, and 117) configured to transport networktraffic, such as user information or network control information. Thesteps of process 400 may be performed in any suitable order or combinedin any suitable manner.

At step 401, one or more optical nodes (e.g., optical nodes 103 and 105)configure one or more component connections (i.e., logical channels)based on a topology of system 100, i.e., based on the establishment ofone or more physical connections (e.g., optical links 107, 109, and117). Individual component connections may be configured over an opticallink (e.g., optical link 107) or over a group of optical links (i.e., apath), such as a path defined by optical links 109 and 117. In thismanner, component connections are independent channels configured fortransporting information, wherein each component connection isindividually characterized by its own transport availability, i.e.,existence, administrative cost, physical bandwidth, provisionedbandwidth, operational status, placement priority, holding priority, andthe like. Thus, in step 403, various component connections may begrouped into one or more CTGs, such that any given CTG (e.g., CTG 203)includes several parallel component connections (e.g., componentconnections 205 a-205 m) establishing a transport route from a desiredpoint “A,” e.g., node 101, to a desired point “B,” e.g., optical node103. For example, system 100 may be characterized by two CTGs, e.g., oneCTG may embody optical link 107 (i.e., a physical component connection)and the conjunction of optical links 109 and 117 (i.e., a logicalcomponent connection or a path), and the second CTG may embody opticallink 109 and the conjunction of optical links 107 and 117. Thecharacteristics of a composite connection (or CTG) may be stored to amemory (not shown) of, for example, optical nodes 103 and 105 and/or anyother suitably accessible repository (not shown) of system 100.According to one embodiment, the CTG characteristics may be stored toone or more tables that provide network traffic visibility so as toenable optical nodes 300 the ability to maximize and efficientlyallocate available bandwidth among various information transportingnodes, e.g., node 101, based on, for instance, composite connectioncharacteristics determined based on and using component connectioncharacteristics. In essence, CTG characteristics aid in the design,implementation, and maintenance of quality of service by providingknowledge of one or more traffic instances. Thus, once one or morecomposite connections are established, the composite connections may beannounced to the network for engineering traffic onto the compositeconnections(s), per step 405. That is, network traffic, such aspacketized optical signals, may be transported over one or morecomponent connections (e.g., component connection 205 a-205 m), whichare defined by one or more optical links (e.g., optical links 107, 109,and 117) based on CTG announcement.

Referring momentarily to FIG. 3, control module 305 may also beconfigured to determine and/or announce TE parameters of a configuredCTG. FIG. 5 is a diagram of a control module configured to determine andannounce traffic engineering parameters of composite transport groups,according to an exemplary embodiment. As shown, control module 500includes administrative cost module 501, announcement module 503,resource monitoring module 505, routing control module 507, and trafficengineering module 509, as well as component connection characteristicsrepository 511, CTG characteristics repository 513, and network topologyrepository 515; however, it is contemplated that control module 500 mayembody many forms. For example, control module 500 may comprisecomputing hardware (such as described with respect to FIG. 8), as wellas include one or more components configured to execute the processesdescribed herein for determining and announcing TE parameters of CTGs.It is contemplated that that the components of control model may becombined, located in separate structures, or separate physicallocations.

In exemplary embodiments, TE module 509 is configured to determine oneor more CTG characteristics (or CTG TE parameters) based on and usingone or more component connection attributes characterizing the componentconnections forming a CTG. Component connection characteristics may beobtained from component connection characteristics repository 511 orfrom any other suitable memory or repository of control module 500,optical node 300, and/or system 100. According to one embodiment,component connection characteristics repository 511 stores informationcorresponding to component connection administrative costs (or TEmetrics), physical bandwidths of component connections, connections (orpathways) on the component connections consuming bandwidth, connectionplacement priorities, connection holding priorities, and/or connectionover-subscription factors. This information may be acquired fromadministrative cost module 501, resource monitoring module 505, and/or anetwork administrator 517 or other network management system (not shown)of system 100.

Administrative cost module 501 can be configured to determine theadministrative costs of component connections based on topologicalinformation stored to network topology repository 515, which may bepopulated by utilizing one or more of the aforementioned signalingand/or routing protocols or pre-configured by a network administrator.Resource monitoring module 505 monitors bandwidth consumption ofconnections provisioned via one or more component connections of a CTG,as well as determines one or more over-subscription factors based on anover-subscribed bandwidth determination. The physical bandwidthcapabilities of component connections, as well as one or more placementpriorities and/or holding priorities, can be supplied by a networkadministrator 517 or other network management system (not illustrated)of system 100. It is further contemplated that one or more of thesecomponent link characteristics may be determined and stored to componentconnection characteristics repository 511 on a per component connectionper priority (or class of service) basis.

Accordingly, TE module 509 includes logic for determining aggregatecharacteristics of a CTG, such as CTG administrative cost, one or moreCTG available bandwidths, and/or one or more maximum LSP bandwidthscapable of being provisioned on the CTG. In certain embodiments, TEmodule 509 determines one or more CTG available bandwidths and one ormore maximum LSP bandwidths on a per component connection per priority(or class of service) basis. Once these aggregate characteristics of aCTG (or CTG TE parameters) are determined, they may be stored to CTGcharacteristics repository 513 or any other suitable memory forprovisioning label switched paths, as well as ported to announcementmodule 503 for announcement to transport network 519. Announced CTG TEparameters can be utilized by transport network 519 (e.g., system 100)for provisioning label switched paths on one or more CTGs. In otherinstances, announcement module 503 can be configured to receive one ormore aggregate CTG characteristics from transport network 519, which mayalso be stored to CTG characteristics repository 513 (or other any othersuitable memory) for provisioning label switched paths onto one or moreCTGs. It is noted that announcement module 503 is also capable ofannouncing and/or receiving aggregate CTG characteristics on a perpriority (or class of service) basis.

In this manner, routing control module 507 may be configured to utilizeinformation stored to CTG characteristics repository 513 to control theflow of traffic through optical switch section 307 of optical node 300.According to other embodiments, CTG characteristics repository 513 maybe accessed by routing control module 507 for the establishment,modification, and/or termination of one or more CTGs, as well as forrouting network traffic through optical switch section 307 and selectingappropriate labels to append to the optical packet headers of opticalpacket payloads routed via optical switch section 307.

Accordingly, CTGs improve transport scalability by reducing the amountof information announced and, thereby, handled by singling and/orrouting protocols, such as OSPF, IS-IS, etc., for the establishment ofone or more traffic pathways. It is noted that this reduction isaccomplished by performing information aggregation (or abstraction)based on and using information characteristic to particular CTGs, i.e.,the attributes defining the characteristics of the component connectionsgrouped into the particular CTGs. Thus, only aggregate CTGcharacteristics (TE parameters) need to be announced, whereas thecharacteristics of the various component connections forming the CTG donot have to be announced. It is contemplated, however, that thecharacteristics of the component connection may be announced, if sodesired.

FIG. 6 is a flowchart of a process for announcing traffic engineeringparameters of composite transport groups, according to various exemplaryembodiments. For the purposes of illustration process 600 is describedwith reference to FIGS. 2 and 5. Moreover, the steps of process 600 maybe performed in any suitable order or combined in any suitable manner.

In step 601, TE module 509 receives information specifyingcharacteristics of a plurality of component links (e.g., componentconnections 205 a-205 m) of a configured CTG (e.g., CTG 203) from, forexample, component connection characteristics repository 511. At step603, TE module 509 determines whether each of the component linksforming the CTG exhibit a same administrative cost. If each of thecomponent links do exhibit the same administrative cost, then, whetheror not each of the component links forming the CTG exhibit a samephysical bandwidth, TE module 509 utilizes a scheme (per Table 1) fordetermining one or more aggregate CTG characteristics, such as a CTGadministrative cost, one or more CTG available bandwidths, and one ormore maximum LSP bandwidths capable of being provisioned on the CTG, perstep 605. In exemplary implementations, the CTG available bandwidths andthe maximum LSP bandwidths are determined per priority.

TABLE 1 Determining Aggregate CTG Characteristics Where all ComponentLinks of CTG Exhibit a Same Administrative Cost AdministrativeAdministrative Cost of Individual Component Links Cost = Available BWTotal CTG BW − Priority 1 BW per Priority 1 = Available BW Total CTG BW− (Priority 1 BW + Priority 2 BW) per Priority 2 = . . . . . . AvailableBW Total CTG BW − (Priority 1 BW + Priority 2 BW + . . . + Priority NBW) per Priority N = Maximum LSP Maximum Component Link Available BWAcross Component Links BW per Priority 1 = per Priority 1 . . . . . .Maximum LSP Maximum Component Link Available BW Across Component LinksBW per Priority N = per Priority N where Total CTG BW = PhysicalComponent Link BW * Number of Component Connections Priority 1 BW = Sumof Provisioned BW for Priority 1 Across all Component Links Priority 2BW = Sum of Provisioned BW for Priority 1 Across all Component Links . .. . . . Priority N BW = Sum of Provisioned BW for Priority N Across allComponent Connections Component Link Component Link Physical BW - Sum ofall Priority 1 Connection BW Available BW * Connection Over-SubscriptionFactor per Priority 1 = . . . . . . Component Link Component LinkPhysical BW - Sum of all Priority 1 Connection BW Available BW *Connection Over-Subscription Factor per Priority N = BW = BandwidthPriority = CTG Connection Holding Priorities Ranging from 1 to 8

If, however, at least one of the component links forming the CTGexhibits a different administrative cost, then TE module 509 mustdetermine whether or not each of the component links forming the CTGexhibit a same physical bandwidth, in step 607. If each of the componentlinks exhibit a same physical bandwidth, then, in step 609, TE module509 utilizes a second scheme, as characterized by the equations of Table2, to determine one or more aggregate CTG characteristics, such as a CTGadministrative cost, one or more CTG available bandwidths, and one ormore maximum LSP bandwidths capable of being provisioned on the CTG. Aswith step 605, in exemplary embodiments, the CTG available bandwidthsand the maximum LSP bandwidths are determined by TE module 509 on a perpriority basis.

TABLE 2 Determining Aggregate CTG Characteristics Where at least oneComponent Link of CTG Exhibits a Different Administrative CostAdministrative Minimum Administrative Cost of all Component Links Cost =Meeting a Predefined Criteria Available BW Component Link Available BWacross Component Links per Priority = that Exhibit a Same Component LinkAdministrative Cost as the CTG Administrative Cost Maximum MaximumComponent Link Available BW Exhibiting a LSP BW per Same Component LinkAdministrative Cost as the CTG Priority = Administrative Cost wherePredefined Component Link Available BW for Priority “X” is Criteria =greater than or equal to “Y” percent of the Physical Component Link BW X= Priority Between 1 and 8 that is Predefined by a Network AdministratorY = Percentage that is Predefined by a Network Administrator

If, however, at least one of the component links forming the CTGexhibits different physical bandwidths, then TE module 509 determineswhether one or more component links is to be removed from theadministrative cost determination, per step 611. Namely, TE module 509determines whether any “relatively very small” bandwidth component linksare bundled with other “relatively large” bandwidth component links toform the CTG. Assuming a relatively very small bandwidth component linkexists, then TE module 509 will remove this component link from thedetermination of the CTG administrative cost, which also subsequentlyeffects the CTG available bandwidth and maximum LSP bandwidthdeterminations. Even if no component links are removed, the processreverts to step 609, i.e., utilizing the scheme of Table 2 to determineone or more aggregate CTG characteristics. As such, a networkadministrator may establish any suitable threshold or percentage valuefor giving effect to the “relatively very small” and “relatively large”nominations. Routing control module 507, however, will still be able toroute network traffic via removed component links by utilizing userspecified routing features made available via one or more MPLS-TEprotocols.

Once the aggregate CTG characteristics are determined, TE module mayport the determined values to announcement module 503 for announcing oneor more of the aggregate CTG characteristics to a transport network,e.g., system 100 (per step 613). The aggregate CTG characteristics canbe announced on a per priority basis, as well. Furthermore, theaggregate CTG characteristics may also be stored to CTG characteristicsrepository 513 or any other suitable memory or repository of controlmodule 500, optical node 300, and/or system 100, for later use.

Accordingly, network traffic may be routed over a CTG based on announcedaggregate CTG characteristics (or TE parameters).

FIG. 7 is a flowchart of a process for routing traffic over a compositetransport group based on announced traffic engineering parameters,according to an exemplary embodiment. For illustrative purposes, process700 is described with reference to FIGS. 1-3 and 5. Moreover, the stepsof process 700 may be performed in any suitable order or combined in anysuitable manner.

In step 701, an ingress node (e.g., client node 101) receives a requestfrom, e.g., an “upstream node” to establish an LSP over a CTG (e.g., CTG203) that is provisioned between the ingress node and an egress node(e.g., optical node 103 or 105). The request to establish the LSP mayinclude various LSP attributes, such as a requested reserved bandwidth,at a particular priority (or class of service), at (or less than) acertain administrative cost. Based on this request, a control module(e.g., control module 305) of the ingress node obtains the aggregatecharacteristics of the CTG from, for example, CTG characteristicsrepository 513, per step 703. In step 705, the control module determineswhether there are sufficient resources available over the CTG bycomparing the LSP request attributes with the aggregate CTGcharacteristics, i.e., the administrative cost, CTG available bandwidthat the requested priority, and/or the maximum LSP bandwidth at therequested priority capable of being provisioned on the CTG. Ifsufficient resources are not available, the ingress node denies therequest, as in step 707, from the “upstream node.” However, if there aresufficient resources available over the CTG, then the request isaccepted and the LSP is established over the CTG, per step 709. When theLSP is established, the entire CTG is specified, such that the CTGselects the particular one or more component connections to host networktraffic, while the “upstream node” merely views and selects the CTG as asingle physical trunk. Thus, in step 711, when traffic is to be routedover the CTG, the traffic is routed transparently from the “upstreamnode,” such that the choice of component link(s) to host network trafficis a local matter to the CTG.

The processes described herein for announcing traffic engineeringparameters for composite transport groups may be implemented viasoftware, hardware (e.g., general processor, Digital Signal Processing(DSP) chip, an Application Specific Integrated Circuit (ASIC), FieldProgrammable Gate Arrays (FPGAs), etc.), firmware or a combinationthereof. Such exemplary hardware for performing the described functionsis detailed below.

FIG. 8 illustrates computing hardware (e.g., computer system) 800 uponwhich an embodiment according to the invention can be implemented. Thecomputer system 800 includes a bus 801 or other communication mechanismfor communicating information and a processor 803 coupled to the bus 801for processing information. The computer system 800 also includes mainmemory 805, such as a random access memory (RAM) or other dynamicstorage device, coupled to the bus 801 for storing information andinstructions to be executed by the processor 803. Main memory 805 canalso be used for storing temporary variables or other intermediateinformation during execution of instructions by the processor 803. Thecomputer system 800 may further include a read only memory (ROM) 807 orother static storage device coupled to the bus 801 for storing staticinformation and instructions for the processor 803. A storage device809, such as a magnetic disk or optical disk, is coupled to the bus 801for persistently storing information and instructions.

The computer system 800 may be coupled via the bus 801 to a display 811,such as a cathode ray tube (CRT), liquid crystal display, active matrixdisplay, or plasma display, for displaying information to a computeruser. An input device 813, such as a keyboard including alphanumeric andother keys, is coupled to the bus 801 for communicating information andcommand selections to the processor 803. Another type of user inputdevice is a cursor control 815, such as a mouse, a trackball, or cursordirection keys, for communicating direction information and commandselections to the processor 803 and for controlling cursor movement onthe display 811.

According to an embodiment of the invention, the processes describedherein are performed by the computer system 800, in response to theprocessor 803 executing an arrangement of instructions contained in mainmemory 805. Such instructions can be read into main memory 805 fromanother computer-readable medium, such as the storage device 809.Execution of the arrangement of instructions contained in main memory805 causes the processor 803 to perform the process steps describedherein. One or more processors in a multi-processing arrangement mayalso be employed to execute the instructions contained in main memory805. In alternative embodiments, hard-wired circuitry may be used inplace of or in combination with software instructions to implement theembodiment of the invention. Thus, embodiments of the invention are notlimited to any specific combination of hardware circuitry and software.

The computer system 800 also includes a communication interface 817coupled to bus 801. The communication interface 817 provides a two-waydata communication coupling to a network link 819 connected to a localnetwork 821. For example, the communication interface 817 may be adigital subscriber line (DSL) card or modem, an integrated servicesdigital network (ISDN) card, a cable modem, a telephone modem, or anyother communication interface to provide a data communication connectionto a corresponding type of communication line. As another example,communication interface 817 may be a local area network (LAN) card (e.g.for Ethernet™ or an Asynchronous Transfer Model (ATM) network) toprovide a data communication connection to a compatible LAN. Wirelesslinks can also be implemented. In any such implementation, communicationinterface 817 sends and receives electrical, electromagnetic, or opticalsignals that carry digital data streams representing various types ofinformation. Further, the communication interface 817 can includeperipheral interface devices, such as a Universal Serial Bus (USB)interface, a PCMCIA (Personal Computer Memory Card InternationalAssociation) interface, etc. Although a single communication interface817 is depicted in FIG. 8, multiple communication interfaces can also beemployed.

The network link 819 typically provides data communication through oneor more networks to other data devices. For example, the network link819 may provide a connection through local network 821 to a hostcomputer 823, which has connectivity to a network 825 (e.g. a wide areanetwork (WAN) or the global packet data communication network nowcommonly referred to as the “Internet”) or to data equipment operated bya service provider. The local network 821 and the network 825 both useelectrical, electromagnetic, or optical signals to convey informationand instructions. The signals through the various networks and thesignals on the network link 819 and through the communication interface817, which communicate digital data with the computer system 800, areexemplary forms of carrier waves bearing the information andinstructions.

The computer system 800 can send messages and receive data, includingprogram code, through the network(s), the network link 819, and thecommunication interface 817. In the Internet example, a server (notshown) might transmit requested code belonging to an application programfor implementing an embodiment of the invention through the network 825,the local network 821 and the communication interface 817. The processor803 may execute the transmitted code while being received and/or storethe code in the storage device 809, or other non-volatile storage forlater execution. In this manner, the computer system 800 may obtainapplication code in the form of a carrier wave.

The term “computer-readable medium” as used herein refers to any mediumthat participates in providing instructions to the processor 803 forexecution. Such a medium may take many forms, including but not limitedto non-volatile media, volatile media, and transmission media.Non-volatile media include, for example, optical or magnetic disks, suchas the storage device 809. Volatile media include dynamic memory, suchas main memory 805. Transmission media include coaxial cables, copperwire and fiber optics, including the wires that comprise the bus 801.Transmission media can also take the form of acoustic, optical, orelectromagnetic waves, such as those generated during radio frequency(RF) and infrared (IR) data communications. Common forms ofcomputer-readable media include, for example, a floppy disk, a flexibledisk, hard disk, magnetic tape, any other magnetic medium, a CD-ROM,CDRW, DVD, any other optical medium, punch cards, paper tape, opticalmark sheets, any other physical medium with patterns of holes or otheroptically recognizable indicia, a RAM, a PROM, and EPROM, a FLASH-EPROM,any other memory chip or cartridge, a carrier wave, or any other mediumfrom which a computer can read.

Various forms of computer-readable media may be involved in providinginstructions to a processor for execution. For example, the instructionsfor carrying out at least part of the embodiments of the invention mayinitially be borne on a magnetic disk of a remote computer. In such ascenario, the remote computer loads the instructions into main memoryand sends the instructions over a telephone line using a modem. A modemof a local computer system receives the data on the telephone line anduses an infrared transmitter to convert the data to an infrared signaland transmit the infrared signal to a portable computing device, such asa personal digital assistant (PDA) or a laptop. An infrared detector onthe portable computing device receives the information and instructionsborne by the infrared signal and places the data on a bus. The busconveys the data to main memory, from which a processor retrieves andexecutes the instructions. The instructions received by main memory canoptionally be stored on storage device either before or after executionby processor.

While certain exemplary embodiments and implementations have beendescribed herein, other embodiments and modifications will be apparentfrom this description. Accordingly, the invention is not limited to suchembodiments, but rather to the broader scope of the presented claims andvarious obvious modifications and equivalent arrangements.

1. A method comprising: receiving information specifying characteristicsof a plurality of component links of a composite transport group;determining an aggregate characteristic of the composite transport groupbased on the information; and announcing the aggregate characteristic toa label switched network for provisioning label switched paths on thecomposite transport group.
 2. A method according to claim 1, wherein thecomponent links have the same administration costs and the same ordifferent physical bandwidths.
 3. A method according to claim 2, whereinthe aggregate characteristic is an administration cost and is equivalentto the administration cost of any individual component link of theplurality.
 4. A method according to claim 2, wherein the aggregatecharacteristic is an available bandwidth for a class of service, and thestep of determining the aggregate characteristic includes, determining atotal bandwidth for the composite transport group, determining a sum ofprovisioned bandwidth for every class of service lower than or equal tothe class of service on each component link of the plurality, andsubtracting the sum from the total.
 5. A method according to claim 2,wherein the aggregate characteristic is a maximum label switched pathbandwidth for a class of service, and the step of determining theaggregate characteristic includes, determining a component linkavailable bandwidth for the class of service for each component link,and determining a maximum across the component link available bandwidthsfor the class of service, wherein the component link available bandwidthfor the class of service for a particular component link is determinedby subtracting a provisioned bandwidth on the particular component linkfor the class of service from a physical bandwidth of the particularcomponent link.
 6. A method according to claim 1, wherein the componentlinks have different administration costs and either the same physicalbandwidths or different physical bandwidths.
 7. A method according toclaim 6, wherein the aggregate characteristic is an available bandwidthfor a class of service, and the step of determining the aggregatecharacteristic includes, determining a component link availablebandwidth for each component link that has a same component linkadministration cost as an aggregate administration cost of the compositetransport group, and determining a sum from these component linkavailable bandwidths, wherein the aggregate administration cost of thecomposite transport group is a minimum across administration costs ofcomponent links meeting a predefined criteria.
 8. A method according toclaim 7, wherein a component link meets the predefined criteria if thecomponent link exhibits an available bandwidth for a specified class ofservice greater than or equal to a specified percentage of a physicalbandwidth of the component link.
 9. A method according to claim 8,wherein one or more component links meeting the predefined criteria areremoved before determining the minimum.
 10. A method according to claim6, wherein the aggregate characteristic is a maximum label switched pathbandwidth for a class of service, and the step of determining theaggregate characteristic includes, determining a component linkavailable bandwidth for the class of service for each component linkthat has a same component link cost as an aggregate administration costof the composite transport group, determining a maximum from thecomponent link available bandwidths, wherein the aggregateadministration cost of the composite transport group is a minimum acrossadministration costs of component links meeting a predefined criteria.11. A method according to claim 1, wherein the information relates toadministration costs, holding priorities, over-subscription factors,physical bandwidths, placement priorities, provisioned bandwidths, or acombination thereof.
 12. An apparatus comprising: a processor configuredto receive information specifying characteristics of a plurality ofcomponent links of a composite transport group, and to determine anaggregate characteristic of the composite transport group based on theinformation, wherein the aggregate characteristic is announced to alabel switched network for provisioning label switched paths on thecomposite transport group.
 13. An apparatus according to claim 12,wherein the component links have the same administration costs and thesame or different physical bandwidths.
 14. An apparatus according toclaim 13, wherein the aggregate characteristic is an administration costand is equivalent to the administration cost of any individual componentlink of the plurality.
 15. An apparatus according to claim 13, whereinthe aggregate characteristic is an available bandwidth for a class ofservice, and the processor is further configured to determine a totalbandwidth for the composite transport group, to determine a sum ofprovisioned bandwidth for every class of service lower than or equal tothe class of service on each component link of the plurality, and tosubtract the sum from the total.
 16. An apparatus according to claim 13,wherein the aggregate characteristic is a maximum label switched pathbandwidth for a class of service, and the processor is furtherconfigured to determine a component link available bandwidth for theclass of service for each component link, and to determine a maximumacross the component link available bandwidths for the class of service,wherein the component link available bandwidth for the class of servicefor a particular component link is determined by subtracting aprovisioned bandwidth on the particular component link for the class ofservice from a physical bandwidth of the particular component link. 17.An apparatus according to claim 12, wherein the component links havedifferent administration costs and either the same physical bandwidthsor different physical bandwidths.
 18. An apparatus according to claim17, wherein the aggregate characteristic is an available bandwidth for aclass of service, and the processor is further configured to determine acomponent link available bandwidth for each component link that has asame component link administration cost as an aggregate administrationcost of the composite transport group, and to determine a sum from thesecomponent link available bandwidths, wherein the aggregateadministration cost of the composite transport group is a minimum acrossadministration costs of component links meeting a predefined criteria.19. An apparatus according to claim 18, wherein a component link meetsthe predefined criteria if the component link exhibits an availablebandwidth for a specified class of service greater than or equal to aspecified percentage of a physical bandwidth of the component link. 20.An apparatus according to claim 19, wherein one or more component linksmeeting the predefined criteria are removed before determining theminimum.
 21. An apparatus according to claim 17, wherein the aggregatecharacteristic is a maximum label switched path bandwidth for a class ofservice, and the processor is further configured to determine acomponent link available bandwidth for the class of service for eachcomponent link that has a same component link cost as an aggregateadministration cost of the composite transport group, and to determine amaximum from the component link available bandwidths, wherein theaggregate administration cost of the composite transport group is aminimum across administration costs of component links meeting apredefined criteria.
 22. An apparatus according to claim 12, wherein theinformation relates to administration costs, holding priorities,over-subscription factors, physical bandwidths, placement priorities,provisioned bandwidths, or a combination thereof.
 23. A systemcomprising: an optical node configured to establish a compositetransport group over a first network, and to convert one or moreinternal traffic engineering parameters specifying link stateinformation relating to the composite transport group to one or moreexternal traffic engineering parameters for use by a second network. 24.A system according to claim 23, wherein the optical node includes anoptical add/drop multiplexer.
 25. A system according to claim 23,wherein the internal traffic engineering parameters include either costof a component link of the composite transport group, bandwidth of thecomponent link, cost of a connection associated with the compositetransport group, bandwidth of the connection, priority informationassociated with the connection, an over-subscription factor for theconnection, or a combination thereof.
 26. A system according to claim23, wherein the external traffic engineering parameters include eithercost for determining a path through the second network, bandwidthinformation, size information of a label switched path, or a combinationthereof.